Qualitative assessment of midstream urine cultures in the detection of bacteriuria.

3550 women attending cervical smear and family planning clinics have been screened for bacteriria. Suprapubic aspiration of urine was carried out in 131 patients from whom two consecutive midstream urine specimens contained either a pure growth of Gram positive cocci or a growth in which Gram negative bacilli predominated. 95 patients were found to have bacteriuria; in 93 the urine was infected with a Gram negative organism. Of 53 patients with a count of more than 10-5 Gram negative organisms per milliliter on two consecutive midstream urine samples, 48 (91%) had bacteriuria. However, 45 (48%) of the 93 patients with bacteriuria did not have two consecutive counts greater than 10-5 organisms per milliliter , and 10 (11%) had counts of less than 10-4 organisms per milliliter in at least one of the two midstream urine samples. It is concluded that midstream urine counts of less than 10-5 organisms per milliliter in which Gram negative bacilli predominate may be indicative of bacteriuria and should be confirmed by suprapubic aspiration.